Open coil electric heater

ABSTRACT

An electric heater for use in a heating appliance, such as a clothes dryer, including a frame member and a heating element supported by and spaced from the frame member. Spool insulators respectively are positioned to surround the heating element and yoke members are connected to the frame and respectively are adapted to receive and retain the spool insulators in snap-in relationship thereby supporting the heating element sections on the frame member. The heater is assembled by threading the spool insulators onto the heating element, arranging the insulators on the heating element in a desired pattern with the insulators respectively aligned with the yoke members of the frame member, and applying force to the insulators to cause the yoke members resiliently to receive and retain the insulator spools. The apparatus for assembling the heater comprises a member respectively having grooves therein for holding the heating element and the spool insulators in a position which allows the frame to be disposed over the assembly member with the yoke members aligned with the spool insulators. A compressive force may then be applied between the member and the frame thereby causing the spool insulators to be resiliently received and retained by the yoke members of the frame.

United States Patent Neuman et a1.

[54] OPEN COIL ELECTRIC HEATER [72] Inventors: Charles E. Neuman, Delphos, Ohio;

Leland R. Shank, Angola, 1nd.

[45] Oct. 10,1972

Primary Examiner-Volodymyr Y. Mayewsky Attorney-Hood, Gust, Irish & Lundy 7] 1 ABSTRACT [7 3] Assignee: Ohio Decorative Products, Inc,

Spencervhle Ohio An electric heater for use in a heating appliance, such as a clothes dryer, including a frame member and a [22] Filed: July 2, 1970 heating element supported by andspaced from the [211 App] 51,971 frame member. Spool insulators respectively are positioned to surround the heating element and yoke members are connected to the frame and respectively are to 338/316 in snap-in relationship thereby supporting the heating [51] Int. Cl. ..H05b 3/06 element Sections on the frame member The heater i [58] Field of Search".. ..219/532, 536-537, assembled by threading the Spool insulators onto the 219/528 338/299 304405 heating element, arranging the insulators on the heat- 174/138 ing element in a desired pattern with the insulators respectively aligned with the yoke members of the [56] References Cmd frame member, and applying force to the insulators to UNITED STATES PATENTS cause the yoke members resiliently to receive and retam the msulator spools. The apparatus for assem- Shaw the heater comprises a member respectively hay- 1,91 NOb1....;... ing grooves therein for the heating element 219214172 H1960 Hackman --219/532 and the spool insulators in a position which allows the 3,016,441 1/1962 ,Hackman et al ..2-19/532 frame to be disposed over the assembly member i 3,019,324 l/ 1962 Sohn ..338/316 X the yoke members aligned with the spool ihsulatom A 3,036,194 5/1962 -De1mnger ..219/532 compressive force m then be applied between the 3,1 19,924 1/ 1964 Kueser ..338/316 X member and the frame thereby causing the Spool i 3,3; I 1(5); lC l)wen.t....l lators to be resiliently received and retained by the 0y 6 a oke members of the frame. 3,522,415 8/1970 Eisler ..'.219/52s y 10 Claims, 16 Drawing Figures I00 4e 1 6 4 K 98 20 as 96 80 l r 5 l 22 26 I II 56 1 i ll I I II! I"! f ll! 30 I F F F 36 LL: I u u a l A \62 r r r I04 4 I04 5,4 42 I04 4 34 1 L; E 38 fl I n n a I 28 II II 86 n T I II4 I 46 52 f 2 24 I20 2 "6 82 {2 I22 mzmsnncrww A 3.697.727 sum Inf 4 INVENTORS CHARLES ElNEUMAN Li R. SHANK LA BY 004)) ATTORNEYS PATENTEnncnman 3.697727 SHEET 2 OF 4 E151 E r 40142 34' H9 I66 /|O4 4 i Q INVENTORS CHARLES E.NEUMAN LAND R SHANK I rw mow W ATTORNEYS PATENTEnncr 10 m2 3.697.727

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INVENTORS CHARLES E,NEUMAN LELAND R. SHANK BYZ/m M, M

ATTORNEYS 1 OPEN COIL ELECTRIC HEATER BACKGROUND OF THE INVENTION same, and more particularly to an electric heating unit of the open coil type for use in heating appliances, such as clothes dryers, and to a method and apparatus for assembling such a heater. 2. Description of the Prior Art In one known type of open coil electric heater, an elongated, helically coiled, resistive heating element is supported on a frame member by means of spool insulators through which the heating element extends, the spools being respectively attached to the frame member. In this prior heater construction, the spool insulators are first attached to the frame, the heating element is then threaded through the insulators, and the two ends of the heating element are then connected to a terminal assembly mounted on the frame.

In another known form of open coil electric heater, the insulator. spools are pre-threaded onto the heating element, and are successively engaged with clip members supported on the heater frame, the clip members receiving the insulator spools in a snap-in relationship.

In the fabrication of such open coil electric heaters, the non-uniform stretching of the heating element results in the formation of relatively hot and cold spots at various points on the heating element when the element is energized, such hot and cold spots resulting in a reduction in the life of the heating element. Both of the prior known heater constructions are susceptible to hot and cold spots such as above-mentioned andrequire time-consuming hand assembly thus adding appreciably to the cost thereof.

SUMMARY OF THE INVENTION In accordance with the invention, we have provided an electric heater construction, and a method and an paratus for assembling the same wherein the heater may be accurately and rapidly assembled in production with less hand labor than heretofore possible, and particularly wherein the heating element is maintained under tension thereby eliminating objectionable hot and cold spots thereon.

In its broader aspects, the electric heater of the invention includes a frame member and an elongated resistive heating element supported thereby, the heating element being spaced from the frame member. A support assembly is provided for the heating element including insulator means, and means for mounting the insulator means on the frame member.

The method of the invention, in its broader aspects, includes the steps of assembling a plurality of insulators on an elongated heating element, arranging said insulators into a predetermined pattern in which the insulators are spaced-apart longitudinally of the heating element, and securing the insulators to a frame.

The assembly apparatus of the invention, in its broader aspects, includes a member having means thereon for removably holding a section of the heating element with a plurality of insulators thereon and means for positioning the'frame member in contact with the insulators.

It is accordingly an object of the invention to provide an improved electricheater.

Another object of the invention is to provide an improved method of assembling an electric heater.

A further object of the invention is to provide im proved apparatus for assembling an electric heater.

Yet another object of the invention is to provide an improved electric heater, and a method and apparatus for assembling the same, wherein the heating element is maintained under uniform tension thereby inhibiting the formation of hot and cold spots.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view showing one embodiment of the improved electric heater of the invention;

FIG. 2 is a side, cross-sectional view taken generally along the line 2-2 of FIG. 1;

FIG. 3 is an end view taken generally along the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary, enlarged view showing a pair of the yoke members employed in the embodiment of the previous figures;

FIG. 5 is an end view of the yoke members of FIG. 4 taken generally along the line 5-5 of fig. 4;

FIG. 6 is a top view of the yoke members of FIGS. 4 and 5;

FIG. 7 is aview showing the blank from which the yoke members of FIGS. 4, 5 and 6 may be fonned;

FIG. 8 is a fragmentary view showing a blank from which a one-piece yoke and frame assembly may be formed;

FIG. 9 is a fragmentary cross-sectional view taken generally along the line 9-9 of FIG. 8;

FIG. 10 is an end view showing the apparatus of the invention for assembling the electric heater of FIGS. 1, 2 and 3;

FIG. 11 is a top view taken generally along the line 11-11 of FIG. 10 and showing one member of the assembling apparatus;

FIG. 12 is a top view taken generally along the line 12-12 of FIG. 10 and showing the other member of the assembling apparatus with a heating element section positioned thereon;

FIG. 13 is a cross-sectional view taken generally along the line 13-13 of FIG. 11;

FIG. 14 is a fragmentary, cross-sectional view taken generally along the line 14-14 of FIG. 12 showing the members of FIGS. 10 and 11 in their operative positions with respect to the frame and heating element, and also illustrating the method of the invention;

FIG. 15 is a fragmentary, cross-sectional view taken generally along the line 15-15 of FIG. 11; and

FIG. 16 is a fragmentary cross-sectional view taken generally along the line 16-16 of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS adapted for use in a domestic clothes dryer. Heater 20 includes a frame assembly generally indicated at 22, and an elongated heating element, generally indicated at 24, formed of helically coiled resistance wire.

Frame 22 comprises a pair of elongated, spaced, parallel frame members 26 and 28 having their forward ends 30 and 32 secured to mounting member 34, as by welding or staking, as shown. Reverse bends 36 and 38 respectively connect forward ends 30 and 32 of frame members 26 and 28 to straight sections 40 and 42. A supporting frame member 44 is provided spaced from bends 36 and 38 and extending transversely across straight sections 40 and 42 of frame members 26 and 28, being secured thereto as by welding, as shown, supporting member 44 having supporting legs 46 depending therefrom, which, in conjunction with mounting member 34 serve to support heater upon a supporting surface.

Heating element 24 is divided into upper and lower, serially connected sections 48, 50 supported in spaced parallel relationship on opposite sides of straight sections 40, 42 of frame members 26 and 28.

In the illustrated embodiment, upper heating element section 48 comprises four elongated reaches 52, 54, 56 and 58, respectively parallel with each other and with frame sections 40, 42, reaches 52-58 being respectively connected by bight portions 60,62 and 64. Lower heating element section 50 similarly comprises four elongated reaches 66, 68, 70 and 72 respectively in vertical alignment with reaches 52-58 of upper heating element section 48. Reaches 66-72 are similarly connected by bight portions 74, 76 and 78, reach 58 of upper section 48 and reach 72 of lower section 50 being connected by a vertically disposed bight portion 80. Ends 82 and 84 of reaches 52 and 66, respectively, which comprise the opposite ends of the entire heating element 24, are respectively connected to terminals 86 and 88 supported in insulating terminal block 90 secured to flange portion 92 of mounting member 34, as by a suitable threaded fastener 94.

Upper and lower heating element sections 48 and 50 are supported on frame sections 40 and 42 by three, spaced support assemblies 96, 98 and 100. Support assemblies 96-100 are substantially identical and thus description of one will suffice. Further, each of the support assemblies 96-100 comprises four identical subassemblies 102 which support the corresponding reaches of the upper and lower heating element sections 48, 50, such as 52 and 66, in spaced parallel relationship with each other and with frame sections 40 and 42, such corresponding reaches being supported in spaced relationship on opposite sides of a horizontal plane 125 including frame sections 40 and 42, and in a vertical plane 128 spaced from the adjacent frame section 40 and 42.

Each of the supporting assemblies 96-100 includes an elongated member 104 extending transversely across frame sections 40 and 42 and having curved portions 106 and 108 which respectively engage frame sections 40 and 42 and are secured thereto, as by welding, member 104 lying generally in the plane 125 defined by frame sections 40 and 42. Each of the members 104 has opposite ends 110, 112 extending outwardly beyond the respective frame section 40 and 42.

Each of the sub-assemblies 102 comprises a pair of spool insulators 114, 116 through which the respective reaches of the upper and lower heating element sections 48 and 50 respectively extend. Each of the spool insulators 114, 116 has an annular, projection 118 formed on its outer periphery intermediate its opposite ends. Insulators 114, 116 of each pair are longitudinally spaced apart in the direction of elongation of frame sections 40, 42.

A pair of yoke members 120, 122 are provided integrally joined by a connecting member 124 which is secured to transverse member 104, as by spot welding in the illustrated embodiment. It will thus be seen that yoke members and 122 respectively face in opposite directions away from plane 125 defined by frame sections 40 and 42. Yoke members 120, 122 respectively resiliently receive and retain spool insulators 114, 116 in a secure snap-in relationship, yoke members 120, 122 having an annular groove 126 formed therein which receives annular projection 118 on the respective spool insulator 114, 116, thus inhibiting longitudinal displacement of the insulator.

It will be seen that connecting members 124 generally lie in plane 125 and extend in spaced parallel relationship with frame sections 40, 42, thus longitudinally spacing yoke members 120, 122 in a direction parallel with frame sections 40, 42. It will further be seen that yoke members 120, 122 respectively support and retain spool insulators 114, 116 so that the corresponding reaches of the upper and lower heating element sections 48, 50 such as 58, 72 (FIG. 3) lie in a vertical plane 128 in spaced parallel relationship with frame sections 40 and 42 and normal to plane 125.

Yoke members 120, 122 and connecting member 124 are preferably integrally formed as a one-piece element which may be stamped and formed from a blank 130, as shown in FIG. 7. It will be seen that blank 130 is initially formed with spaced, parallel ears 132, 134 joined to the opposite sides of connecting member 124 adjacent end 136, and spaced parallel ears 138, joined to the opposite sides of connecting member 124 adjacent its other end 142. In the forming operation, ears 132, 134 are respectively bent downwardly along lines 144, 146, upwardly along line 148 and outwardly along lines 150, 152, ears 132, 134 also being formed into their generally arcuate shape and having the groove 126 formed therein thereby to form yoke member 120. Ears 138, 140 are similarly formed in the opposite direction thereby to form yoke member 122.

Inspection of FIG. 5 will reveal that ears 132, 134 of yoke member 120, and ears 138, 140 of yoke member 122 are formed with an arcuate curvature with conforms to the cylindrical outer surfaces of spool insulators 114, 116, and that the ears 132, 134, 138 and 140 have a length so as to extend the outer extremities 154 outwardly somewhat beyond the center lines 156, 158 of insulators 114, 116, thereby to provide for resiliently receiving and retaining spool insulators 114, 116 in snap-in relationship, a light force being required to be applied to the insulators 114, 116 respectively inwardly toward yoke members 120, 122, as shown by the arrows 160, 162, in order to cause yoke members 120, 122 resiliently to engage the insulators.

It will now be seen that the provision of the transverse members 104 which respectively extend across and are secured to the longitudinally extending frame sections 40 and 42 contribute additional rigidity to the heater thereby inhibiting distortion of frame sections 40 and 42 and consequent distortion of the reaches of the heating element 24. Further, the formation of the yoke members 120, 122 and the connecting members 124 as a single, one-piece element contributes further rigidity to the structure to the end that the reaches of the upper and lower heating element sections 48, 50 are atall times supported and maintained in the desired relationship. Further, as will be described hereinafter, heating element 24 may be assembled by an operation, as a result of which the heating element is uniformly stretched and maintained in uniform tension by the attachment of ends 82, 84 to terminals 86, 88, thereby inhibiting sagging of the reaches of the heating element between adjacent spool insulators and the formation of hot and cold spots. The central openings of insulators 114, 116 are sufficiently large to accommodate longitudinal movement of the respective heating element reach therein, thereby to accommodate the initial tensioning of the heating element and subsequent expansion and contraction of theelement caused by its energization and deenergization. Thus, the improved electric heater construction of the invention maintains the reaches of the upper and lower heating element sections 48, 50 in the desired straight, parallel relationship and under uniform tension throughout thereby providing a more rigid structure in which undesirable hot an cold spots are eliminated.

Referringnow to FIGS. 8 and 9, it will be seen that the blank 130 from which the yoke members 120, 122 and connecting members 124 are formed may be integrally formed with transverse members 104' as a single, one-piece element, thereby providing additional rigidity. Further, longitudinally extending frame sections 40', 42' may be integrally formed with transverse members 104', a longitudinally extending groove 166 being formed in the frame sections 40, 42' in order to contribute the requisite rigidity. Still further, it will be seen that a mounting member 34' may likewise be integrally formed with the frame sections 40', 42, with the result that the entire supporting frame assembly may be integrally fonned as a single, one-piece element, thus completely eliminating the need for performing welding operations.

Referring now to FIGS. -16 of the drawings, the method and apparatus for assembling the electric heater of the invention will be described. The apparatus, generally identified at 168 in FIG. 10, comprises a supporting frame 170 having elements 172, 174 which mutually define an upwardly facing V- shaped configuration. A first form member 176 is rigidly attached to frame element 172. A second form member 178 is mounted on frame 170 by means of links 180 pivotally connected to form member 178, as at 182 and to base element 184 adjacent the apex of the V defined by elements 172, 174, as at 186. Form member 178 may thus be moved between a first position in engagement with frame element 174, as shown in solid lines in FIG. 10, and a second position in spaced parallel relationship with form member 176, as shown in dashed lines at 178a.

Form member 178 has a groove 188 formed therein for receiving upper heating element section 48, groove 188 having a pattern corresponding to that of heating element section 48. Groove 188 has recesses 190 formed therein for respectively receiving and locating insulator spools 114. A slotted member 192 is provided adjacent end 194 of groove 188 for receiving and retaining a convolution of reach 52 of upper heating element section 48 adjacent its end 82, thereby to permit initial tensioning of the heating element.

Bight portions 196, 198 of groove 188 which accommodate bight portions 60, 64, respectively, of upper heating element section 48 are somewhat elongated in order to permit tensioning of the upper heating element section 48.

Longitudinally extending slots 200 are formed in form member 178 communicating with bight portions 196, 198 of the groove 188, as best seen in FIGS. 11 and 15. Movable knobs 202 are provided adjacent bight portions 196, 198 mounted on rods 204 which extend through slots 200 and which are biased in the direction shown by the arrow 206 by springs 208 (FIG. 15) so that knobs 202 engage the respective bight portion 60, 64 of the upper heating element section 48 thereby to urge the same in direction 206 away from the opposite ends of therespective reaches so as, to apply tension on the heating element section. A fixed knob 210 is disposed at bight portion 212 which accommodates bight portion 62 of upper heating element section 48 and is adapted to have bight portion 62 trained therearound. A clip 214 is pivotally mounted on form member 178, as at 216, for releasably clamping end 218 of reach 58 of the upper heating element section 48 adjacent bight portion (FIG. 1). A handle member 219 is provided attached to form member 178 for the purpose to be hereinafter described.

Form member 176 has a similar groove 188 with recesses 190 formed therein, grooves and 188', and recesses 190, being respectively positioned and arranged so that when the movable form member 178 is moved to its position as shown in dashed lines at 178a in FIG. 10 in spaced parallel relationship with the fixed form member 176, grooves 180, 180' and recesses 190, 190 are properly positioned so as to locate the upper and lower heating element sections 48, 50 and the spool insulators 114, 116 in the proper relationship for assembly of the frame thereon. Fixed form member 176 is similarly provided with slots 200' communicating with bight portions 196', 198' and with the spring-biased knobs 202 and fixed knob 210. Slotted member 192' is likewise provided adjacent end 194 of groove 188' for receiving one convolution of reach 66 of the lower heating element section 50 adjacent end 84. Pivoted clamp member 214' releasably clamps end 218' of reach 72 adjacent bight portion 80. Slots 222 are formed in end 224 of fixed form member 176 to receive reverse bend portions 38 of frame sections 40, 42, as best seen in FIG. 14.

In the assembly of the heater, spool insulators 114, 116 are first threaded onto the heating element 50 in spaced-apart relationship. End portion 225 adjacent end 82 is then seated in the slot 226 of member 192 on movable form member 178 and the upper heating element section 48 is then formed by positioning the heating element in groove 188 with the spool insulators l 14 seated in recesses 190, the heating element being trained around spools 202 and 210 and end portion 218 then clamped by clamping member 214. It will be observed that the bottom edges 228, 230 of the movable and fixed form members 178, 176 are closely adjacent and thus bight portion 80 is formed as the lower heating element section 50 is formed by placing the heating element in group 188' and training it around spools 202 and 210' of the fixed form member 176, spool insulators 116 again being positioned in recesses 190'. Finally, end portion 232 of reach 66 adjacent end 84 is seated in slot 226 of member 192 and clamp member 214' is pivoted to its position as shown in FIG. 12. Thus, it will be seen that heating element 24 has been disposed in grooves 188, 188 of the complementary form members 176, 178 and releasably retained therein by the cooperative action of slotted members 192, 192', clamps 214, 214', fixed knobs 210, 210' and spring-biased knobs 202, 202 which initially tension the reaches of the upper and lower heating element sections 48, 50 with the reaches thus having the requisite straight configuration.

Frame assembly 22 is now positioned over fixed form member 176 and the lower heating element section 50 positioned therein,.reverse bends 38 of frame sections 40, 42 being received in slots 222, and yoke members 122 being respectively aligned with and contacting spool insulators 1 16, but not yet being forced into snapin engagement therewith (FIG. 14). The movable form member 178 is then moved to its position shown in dashed lines at 178a (FIG. 10) in spaced parallel relationship with the fixed form member 176, frame assembly 22 thus being disposed between the fixed and movable form members 178, 176 with yoke members 120 in alignment with and contacting spool insulators 1 14, but not yet being forced into snap-in engagement therewith (FIG. 14). Ends 82, 84 of heating element 24 are then secured to terminals 86, 88 thus to maintain the previously applied uniform tension on the heating element.

Compressive force is then manually applied by means of lever members 219, 219' in the direction shown by the arrows 160, 162 (FIG. 14) thereby to force spools 114, 116 into snap-in engagement with yoke members 120, 122, as above-described. Clamps 214, 214' are then manually pivoted away from their clamping engagement with the portions of the heating element adjacent bight portion 80, and the movable form member 178 is then returned to its position shown in solid lines in FIG. 10 by means of handle member 219, thus leaving the completed heater assembly resting upon the fixed form member 178 from which it then can be removed.

It will now be seen that the invention provides a method and apparatus for assembling the improved electric heater of the invention which greatly facilitates the assembly operation, eliminates a multiplicity of hand operations previously performed, places the heating element under the requisite tension, and which provides uniformity in production.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What is claimed is:

1. In an electric heater including a frame and an elongated resistive heating element supported thereby, said heating element having first and second sections respectively spaced from each other and from said frame; a support assembly for said heating element sections including first and second insulators connected to said heating element; and means for mounting said insulators on said frame with said first and second heating element sections being supported in spaced-apart relationship with each other and said frame, said mounting means including first and second means respectively facing in opposite directions for respectively receiving and retaining said first and second insulators in snap-in relationship, and means connected to said frame for maintaining said heating element under uniform tension, said insulators accommodating relative longitudinal movement of said heating element sections, said heating element being formed of coiled resistance wire.

2. The heater of claim 1 wherein said heating element includes third and fourth elongated sections, all of said heating element sections being in spaced relationship with each other and with said frame; and further comprising a second support assembly for said third and fourth heating element sections comprising third and fourth insulators respectively engaging said third and fourth heating element sections, and second means for mounting said third and fourth insulators on said frame with said third and fourth heating element sections being thereby supported in spaced-apart relationship with each other and said frame, said second mounting means including third and fourth means respectively facing in the same directions as said first and second receiving means for respectively receiving said third and fourth insulators in snap-in relationship; said first-named mounting means including first means for connecting said first and second receiving means, said second mounting means including second means for connecting said third and fourth receiving means; and third means for connecting said first and second connecting means to said frame.

3. In an electric heater including a frame and an elongated resistive heating element supported thereby, said heating element having first and second sections respectively spaced from each other and from said frame; a support assembly for said heating element sections including first and second insulators connected to said heating element; means for mounting said insulators on said frame with said first and second heating element sections being supported in spaced-apart relationship with each other and said frame, said mounting means including first and second means respectively facing in opposite directions for respectively receiving and retaining said first and second insulators in snap-in relationship, means connected to said frame for maintaining said heating element under uniform tension, said insulators accommodating relative longitudinal movement of said heating element sections, said frame being elongated, said mounting means including first means for connecting said first and second receiving means, said first connecting means being in generally spaced parallel relationship with said frame and spacing said receiving means apart in a direction parallel with said frame, and second means for connecting said first connecting means to said frame and extending generally transversely thereto.

4. The assembly of claim 3 wherein said first and second receiving means and said first connecting means comprise a one-piece element.

5. The assembly of claim 3 wherein said first and second receiving means and said first and second connecting means comprise a one-piece element.

6. The assembly of claim 3 wherein said first and second receiving means, said first and second connecting means, and said frame comprise a one-piece element.

7. The heater of claim 3 wherein said frame includes a mounting member connected to'said frame, said first and second receiving means, said first and second connecting means, said frame, and said mounting member comprising a one-piece element.

8. The heater of claim 3 wherein said heating element includes third and fourth elongated sections, all of said heating element sections being in spaced relationship with each other and with said frame, and further comprising a second support assembly for said third and fourth heating element sections substantially duplicative of said first-named support assembly, said first connecting means of said second support assembly being generally parallel with said frame, said second connecting means of said first assembly also comprising the second connecting means of said second assembly.

9. The assembly of claim 3 wherein said insulators comprise first and second spools which surround the respective heating element section, said receiving means comprising first and second yoke members which resiliently receive and retain the respective spools.

10. The assembly of claim 9 wherein said heating element is formed of helically coiled resistance wire, said frame element being elongated, said first and second heating element sections being in spaced, parallel relationship respectively on opposite sides of a first plane including said frame, and lying in a second plane normal to said first plane and in spaced, parallel relationship with said frame, said first and second yoke members being respectively positioned on opposite sides of said first plane and respectively facing outwardly in opposite directions away from said first plane, said yoke members being spaced apart in a direction parallel with said frame; said mounting means further comprising a first memberconnecting said yoke members, said first connecting member generally lying in said first-named plane and being in generally spaced, parallel relationship with said frame, and a second member connecting said first connecting member to said frame and extending generally transversely thereto; and further comprising first and second terminals mounted on said frame, said heating element having opposite ends respectively connected to said terminals and being maintained in tension throughout its length thereby, said spools accommodating relative longitudinal movement of said heating element. 

1. In an electric heater including a frame and an elongated resistive heating element supported thereby, said heating element having first and second sections respectively spaced from each other and from said frame; a support assembly for said heating element sections including first and second insulators connected to said heating element; and means for mounting said insulators on said frame with said first and second heating element sections being supported in spaced-apart relationship with each other and said frame, said mounting means including first and second means respectively facing in opposite directions for respectively receiving and retaining said first and second insulators in snapin relationship, and means connected to said frame for maintaining said heating element under uniform tension, said insulators accommodating relative longitudinal movement of said heating element sections, said heating element being formed of coiled resistance wire.
 2. The heater of claim 1 wherein said heating element includes third and fourth elongated sections, all of said heating element sections being in spaced relationship with each other and with said frame; and further comprising a second support assembly for said third and fourth heating element sections comprising third and fourth insulators respectively engaging said third and fourth heating element sections, and second means for mounting said third and fourth insulators on said frame with said third and fourth heating element sections being thereby supported in spaced-apart relationship with each other and said frame, said second mounting means including third and fourth means respectively facing in the same directions as said first and second receiving means for respectively receiving said third and fourth insulators in snap-in relationship; said first-named mounting means including first means for connecting said first and second receiving means, said second mounting means including second means for connecting said third and fourth receiving means; and third means for connecting said first and second connecting means to said frame.
 3. In an electric heater including a frame and an elongated resistive heating element supported thereby, said heating element having first and second sections respectively spaced from each other and from said frame; a support assembly for said heating element sections including first and second insulators connected to said heating element; means for mounting said insulators on said frame with said first and second heating element sections being supported in spaced-apart relationship with each other and said frame, said mounting means including first and second means respectively facing in opposite directions for respectively receiving and retaining said first and second insulators in snap-in relationship, means connected to said frame for maintaining said heating element under uniform tension, said insulators accommodating relative longitudinal movement of said heating element sections, said frame being elongated, saiD mounting means including first means for connecting said first and second receiving means, said first connecting means being in generally spaced parallel relationship with said frame and spacing said receiving means apart in a direction parallel with said frame, and second means for connecting said first connecting means to said frame and extending generally transversely thereto.
 4. The assembly of claim 3 wherein said first and second receiving means and said first connecting means comprise a one-piece element.
 5. The assembly of claim 3 wherein said first and second receiving means and said first and second connecting means comprise a one-piece element.
 6. The assembly of claim 3 wherein said first and second receiving means, said first and second connecting means, and said frame comprise a one-piece element.
 7. The heater of claim 3 wherein said frame includes a mounting member connected to said frame, said first and second receiving means, said first and second connecting means, said frame, and said mounting member comprising a one-piece element.
 8. The heater of claim 3 wherein said heating element includes third and fourth elongated sections, all of said heating element sections being in spaced relationship with each other and with said frame, and further comprising a second support assembly for said third and fourth heating element sections substantially duplicative of said first-named support assembly, said first connecting means of said second support assembly being generally parallel with said frame, said second connecting means of said first assembly also comprising the second connecting means of said second assembly.
 9. The assembly of claim 3 wherein said insulators comprise first and second spools which surround the respective heating element section, said receiving means comprising first and second yoke members which resiliently receive and retain the respective spools.
 10. The assembly of claim 9 wherein said heating element is formed of helically coiled resistance wire, said frame element being elongated, said first and second heating element sections being in spaced, parallel relationship respectively on opposite sides of a first plane including said frame, and lying in a second plane normal to said first plane and in spaced, parallel relationship with said frame, said first and second yoke members being respectively positioned on opposite sides of said first plane and respectively facing outwardly in opposite directions away from said first plane, said yoke members being spaced apart in a direction parallel with said frame; said mounting means further comprising a first member connecting said yoke members, said first connecting member generally lying in said first-named plane and being in generally spaced, parallel relationship with said frame, and a second member connecting said first connecting member to said frame and extending generally transversely thereto; and further comprising first and second terminals mounted on said frame, said heating element having opposite ends respectively connected to said terminals and being maintained in tension throughout its length thereby, said spools accommodating relative longitudinal movement of said heating element. 